Molten metal handling system

Abstract

There is disclosed a combination of several novel elements in combination with improved designs of existing elements, to provide a relatively simple means for delivering high melting molten metals, such as magnesium and its alloys, to a continuous caster without exposure of the metal to the ambient atmosphere, at reproducible pressures and quantities to enable the advanced casting technologies to be utilized to their fullest potential. Thus in accordance with the present invention there is described a molten metal handling system, particularly useful for delivering high melting temperature metals in their molten state from a melting pot or crucible to a casting machine, e.g. die caster, strip caster, sand molds and the like, remote from the melting pot or crucible without exposure to the ambient atmosphere. The essential elements of the present molten metal handling system are a pump and heated conduits to carry the molten metal to the casting station. Preferred elements in addition to the pump and conduit are flowmeters and flow control elements. Optionally, two or more sources of molten metal, e.g. two remote crucible or melting pots, can be tied together to provide a continuous source of metal to one or more die casters or strip caster.

What is claimed is: 
     
       1. A method for delivering molten metal from a molten metal source, a melting or holding pot, to a desired location, including a mold or die, without exposure of the molten metal to the atmosphere, which comprises (1) pumping said molten metal from said molten metal source employing a pump having no external cooling means employing a conventional mica which has been heat treated to at least the maximum temperature to which the pump will be subjected and operating on the principle of magnetohydrodynamics (MHD) completely immersed in the molten metal source,   (2) transporting the molten metal from the outlet of said pump through a heated conduit or series of heated conduits providing a path for molten metal delivered by the pump to access the desired use location, said conduits being insulated electrically heated tubes non-reactive with the metal being carried.   
     
     
       2. The method of claim 1 wherein intermediate said pump and said desired location there is provided a metal flow measuring device consisting of a three or five coil MHD apparatus wherein the middle coil or 2nd and 4th coils generate a voltage from the current developed on the molten passing the said coil, the outer coils being powered. 
     
     
       3. The method of claim 1 wherein intermediate said pump and said desired location there is provided; (a) a metal flow measuring device consisting of an annular linear three or five coil MHD apparatus wherein the middle or 2nd and 4th coils generate a voltage from the current developed on the molten metal passing the said coil(s), the outer coils of said three coil apparatus and the outer and 3rd coils of the five coil apparatus being powered;   (b) a shot size measuring and delivery means consisting of a shot delivery device having a chamber, a molten metal inlet, an inert gas inlet and a cylinder for moving molten metal which on movement forward seals the molten metal inlet then the gas inlet as it moves the metal into the mold, and opens the gas inlet and then the molten metal inlet as it, the cylinder, is retracted from it forward position, said cylinder being of a size sufficient to contain and deliver, under appropriate pressure of the metal at the metal inlet, the desired amount of metal to the mold.   
     
     
       4. The method of claim 1 wherein intermediate said pump and said desired location there is provided: (a) a metal flow measuring device consisting of a flat linear three or five coil MHD apparatus wherein the middle coil or 2nd and 4th coils generate a voltage from the current developed on the molten metal passing the said coil, the outer coils being powered,   (b) a shot size measuring and delivery means consisting of a shot delivery device having a chamber, a molten metal inlet, an inert gas inlet, a molten metal movement and gas and molten metal inlet sealing cylinder for delivering the measured amount of molten metal from the conduit located in said system adjacent to the sprue of said die casting machine die.   
     
     
       5. The method of claim 1 wherein a series of two or more die casting machines are fed molten metal from at least one or more inter connected melting pots and wherein intermediate said pump and said desired location there is provided: (a) a metal flow measuring device consisting of a linear three or five coil MHD apparatus wherein the middle coil or 2nd and 4th coils generate a voltage from the current developed on the molten metal passing the said coil, the outer coils being powered,   (b) a shot size measuring and delivery means consisting of a shot delivery device having a chamber, a molten metal inlet, an inert gas inlet, a molten metal movement and gas and molten metal inlet sealing cylinder for delivering the measured amount of molten metal from the conduit located in said system adjacent to the sprue of each associated die casting machine, and each shot size and delivery means being connected to said main conduit by a separate conduit having an orifice therein proportionated to provide the required metal volume necessary to fill the specific mold at the pressure selected for the system.